Genomic surveillance reveals multiple introductions of SARS-CoV-2 into Northern California by Deng, X, Gu, W, Federman, S, du Plessis, L, Pybus, OG, Faria, N, Wang, C, Yu, G, Bushnell, B, Pan, C-Y, Guevara, H, Sotomayor-Gonzalez, A, Zorn, K, Gopez, A, Servellita, V, Hsu, E, Miller, S, Bedford, T, Greninger, AL, Roychoudhury, P, Starita, LM, Famulare, M, Chu, HY, Shendure, J, Jerome, KR, Anderson, C, Gangavarapu,K, Zeller, M, Spencer, E, Andersen, KG, MacCannell, D, Paden, CR, Li, Y, Zhang, J, Tong, S, Armstrong, G, Morrow, S, Willis, M, Matyas, BT, Mase, S, Kasirye, O, Park, M, Masinde, G, Chan, C, Yu, AT, Chai, SJ, Villarino, E, Bonin, B, Wadford, DA, Chiu, CY